Craftsman Garage Door Opener Model 139.53413 - Won't stop running

reeseoJanuary 27, 2008

I've just finished replacing the drive gear and worm gear on a Sears/Craftsman garage door opener. When I plug it in it just keeps running. The travel lift adjustment turns until the little metal contact travels past the up/down contact. I have turned the adjustment so that it touched either up or down contact but it still runs. I've checked the four pin circuit board plug to make sure I had it on right and checked all other wires/connections. I've also pulled the black cap off the end of the drive shaft and made sure it's on as far as I can get it. Any ideas what I should try next? Thanks

Make sure the grey wire is connected to the center contact on the limits. In other words the white threaded rod that is driven by the very small gear on the bottom of the shaft. Make sure that small white gear is on the bottom of the shaft with the triton shaped keeper. Make sure the prongs that make contact with the up and down limit are not bent. If the opener worked fine up until the gear wore out, I would think that there is something being over looked. If everything checks out ok you can try to file the contacts and see if that fixes it otherwise you are looking at a circuit board or limit switch assembly gone bad. Double check everything and let us know what you find.